Abstract: A sensitive and specific ELISA for human thyrotropin(hTSH) is established by using two anti hTSH monoclonal antibody. One of them is coated on the microtiter plate, the other is conjugate of biotin. The label is horseradish peroxidase(HRP) conjugate of streptavidin. TMB H 2O 2 solution is used as the substrate of HRP. The sensitivity of the assay is 0.02 mIU/L. The intra assay CVs and the intre assay CVs of 3 samples are all lower than 10%. The analytical recovery is in the range from 93.3% to 107.8%. The assay is specific for hTSH and no cross reaction with other glyco proteins, such as hLH, hHCG, hFSH. TSH concentrations range from 0.3 to 4.1 mIU/L in 142 normal subjects. For a reference IRMA(Multipact) method, the correlation regression equation of present method is y=1.2x IRMA +0.14(mIU/L)( r =0.969). This method is a rapid, sensitive, convenient and inexpensive method for measuring hTSH in human serum. It is suitable for clinical and research application.